ext4: Convert callers of ext4_get_blocks() to use ext4_map_blocks()
This saves a huge amount of stack space by avoiding unnecesary struct
buffer_head's from being allocated on the stack.
In addition, to make the code easier to understand, collapse and
refactor ext4_get_block(), ext4_get_block_write(),
noalloc_get_block_write(), into a single function.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 37f9387..d6801eb7 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3667,13 +3667,12 @@
long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len)
{
handle_t *handle;
- ext4_lblk_t block;
loff_t new_size;
unsigned int max_blocks;
int ret = 0;
int ret2 = 0;
int retries = 0;
- struct buffer_head map_bh;
+ struct ext4_map_blocks map;
unsigned int credits, blkbits = inode->i_blkbits;
/*
@@ -3687,13 +3686,13 @@
if (S_ISDIR(inode->i_mode))
return -ENODEV;
- block = offset >> blkbits;
+ map.m_lblk = offset >> blkbits;
/*
* We can't just convert len to max_blocks because
* If blocksize = 4096 offset = 3072 and len = 2048
*/
max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
- - block;
+ - map.m_lblk;
/*
* credits to insert 1 extent into extent tree
*/
@@ -3706,16 +3705,14 @@
}
retry:
while (ret >= 0 && ret < max_blocks) {
- block = block + ret;
- max_blocks = max_blocks - ret;
+ map.m_lblk = map.m_lblk + ret;
+ map.m_len = max_blocks = max_blocks - ret;
handle = ext4_journal_start(inode, credits);
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
break;
}
- map_bh.b_state = 0;
- ret = ext4_get_blocks(handle, inode, block,
- max_blocks, &map_bh,
+ ret = ext4_map_blocks(handle, inode, &map,
EXT4_GET_BLOCKS_CREATE_UNINIT_EXT);
if (ret <= 0) {
#ifdef EXT4FS_DEBUG
@@ -3729,14 +3726,14 @@
ret2 = ext4_journal_stop(handle);
break;
}
- if ((block + ret) >= (EXT4_BLOCK_ALIGN(offset + len,
+ if ((map.m_lblk + ret) >= (EXT4_BLOCK_ALIGN(offset + len,
blkbits) >> blkbits))
new_size = offset + len;
else
- new_size = (block + ret) << blkbits;
+ new_size = (map.m_lblk + ret) << blkbits;
ext4_falloc_update_inode(inode, mode, new_size,
- buffer_new(&map_bh));
+ (map.m_flags & EXT4_MAP_NEW));
ext4_mark_inode_dirty(handle, inode);
ret2 = ext4_journal_stop(handle);
if (ret2)
@@ -3765,42 +3762,39 @@
ssize_t len)
{
handle_t *handle;
- ext4_lblk_t block;
unsigned int max_blocks;
int ret = 0;
int ret2 = 0;
- struct buffer_head map_bh;
+ struct ext4_map_blocks map;
unsigned int credits, blkbits = inode->i_blkbits;
- block = offset >> blkbits;
+ map.m_lblk = offset >> blkbits;
/*
* We can't just convert len to max_blocks because
* If blocksize = 4096 offset = 3072 and len = 2048
*/
- max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
- - block;
+ max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
+ map.m_lblk);
/*
* credits to insert 1 extent into extent tree
*/
credits = ext4_chunk_trans_blocks(inode, max_blocks);
while (ret >= 0 && ret < max_blocks) {
- block = block + ret;
- max_blocks = max_blocks - ret;
+ map.m_lblk += ret;
+ map.m_len = (max_blocks -= ret);
handle = ext4_journal_start(inode, credits);
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
break;
}
- map_bh.b_state = 0;
- ret = ext4_get_blocks(handle, inode, block,
- max_blocks, &map_bh,
+ ret = ext4_map_blocks(handle, inode, &map,
EXT4_GET_BLOCKS_IO_CONVERT_EXT);
if (ret <= 0) {
WARN_ON(ret <= 0);
printk(KERN_ERR "%s: ext4_ext_map_blocks "
"returned error inode#%lu, block=%u, "
"max_blocks=%u", __func__,
- inode->i_ino, block, max_blocks);
+ inode->i_ino, map.m_lblk, map.m_len);
}
ext4_mark_inode_dirty(handle, inode);
ret2 = ext4_journal_stop(handle);